But the role of contract diminishes further if we turn our attention to those reasons for rejection. Why not suppose that they themselves provide the very reasons an action is wrong, short-circuiting any residual appeal to contracts with others? Suppose it is reasonable to reject my principles because, for instance, they lead to vast inequalities of wealth. Why then isn't that the very feature that makes my principles wrong? Why go through the detour of dragging in the hypothetical agreement with others? The question becomes particularly pointed when we think of actions that are supposed to be wrong although the harm is done to a creature or even a thing that is incapable of making contracts: aborting a fetus, tormenting animals or flooding the Grand Canyon for water-skiing. About this last kind of case Scanlon admits that ''the idea that there is a moral objection to harming or defacing works of nature (apart from any effects this has on human life) is adequately explained by the fact that the character of these objects -- such as their grandeur, beauty and complexity -- provides compelling reason not to harm them. Nothing would be added by bringing in the idea of what a trustee for these objects would have reason to reject.'' But then one might suppose that the character of other things we care about -- such as misery, pain or death -- provides compelling moral reasons as well, just by itself [to reject actions].

2. Contractualism’s focus on individualism leads to the justification of unmoral actions. Ashford and Mulgan describe:

“Contractualism.” Elizabeth Ashford, Tim Mulgan. [Elizabeth is lecturer in Moral Philosophy at the University of St. Andrews. Tim is a Professor of Moral and Political Philosophy at the University of St. Andrews.] Stanford Encyclopedia of Philosophy. Aug 30, 2007. http://plato.stanford.edu/entries/contractualism/#ConCirRed.

Consider the following situation, drawn from a famous article by John Taurek (Taurek 1977).The Rocks. Six innocent swimmers have become trapped on two rocks by the incoming tide. Five of the swimmers are on one rock, while the last swimmer is on the second rock. Each swimmer will drown unless they are rescued. You are the sole life-guard on duty. You have time to get to one rock in your patrol-boat and save everyone on it. Because of the distance between the rocks, and the speed of the tide, you cannot get to both rocks in time. What should you do? Suppose you decide to save the lone swimmer on the second rock. Intuitively, this seems wrong. Surely you should have saved five people instead of one. The challenge for contractualism is to explain why what you did is wrong. Utilitarians have a straightforward answer, based on aggregation. You should save the five people instead of the one simply because five deaths is a worse result than one death. This case is tricky for contractualism because it rejects aggregation. The five people will each want to reject the principle that allows you to save the one, by appealing to the fact that such a principle leaves them to die. But the lone person on the second rock will want to reject any principle that allows you to save the five. And the reason for objecting to the principle is exactly the same in each case — this principle leaves that person to die. The five people cannot appeal to the fact that there are more of them — because this is not an individual reason.

3. Using contractualism fails as it is impossible to find a set of generally agreed upon principles. Ashford and Mulgan 2 write:

“Contractualism.” Elizabeth Ashford, Tim Mulgan. [Elizabeth is lecturer in Moral Philosophy at the University of St. Andrews. Tim is a Professor of Moral and Political Philosophy at the University of St. Andrews.] Stanford Encyclopedia of Philosophy. Aug 30, 2007. http://plato.stanford.edu/entries/contractualism/#ConCirRed.

A similar problem for Contractualism is presented by Thomas Nagel, who argues that, in the present state of the world, it may be impossible to construct any set of principles which no-one can reasonably reject. Any possible principle of aid will either make unreasonable demands on the affluent (from their point of view), or pay inadequate attention to the basic needs of the destitute (from their point of view). If the notion of reasonable rejection is at least partly determined by the agent's own perspective, then any principle will be reasonably rejected by someone. (Nagel 1991 and 1999).

4. Contractualism is undesirable as a guide to action compared to utilitarianism as it leaves out considerations for animals. Ashford and Mulgan 3 write:

“Contractualism.” Elizabeth Ashford, Tim Mulgan. [Elizabeth is lecturer in Moral Philosophy at the University of St. Andrews. Tim is a Professor of Moral and Political Philosophy at the University of St. Andrews.] Stanford Encyclopedia of Philosophy. Aug 30, 2007. http://plato.stanford.edu/entries/contractualism/#ConCirRed.

Social contract theories notoriously leave out non-human animals. If all moral obligations are between parties to the social contract, then we have no obligations regarding animals who cannot be parties to the contract. So (for instance) torturing non-rational animals cannot be wrong. By contrast, utilitarians have no difficulty explaining why it is wrong to torture animals. This seems to place contractualism at a comparative disadvantage.

5. Contractualism also leaves out obligations to future people, making utilitarianism take into account a greater number of relevant considerations. Ashford and Mulgan 4 write:

“Contractualism.” Elizabeth Ashford, Tim Mulgan. [Elizabeth is lecturer in Moral Philosophy at the University of St. Andrews. Tim is a Professor of Moral and Political Philosophy at the University of St. Andrews.] Stanford Encyclopedia of Philosophy. Aug 30, 2007. http://plato.stanford.edu/entries/contractualism/#ConCirRed.

Another problem facing any social contract theory concerns our obligations to future people. It is hard to see how we can have any obligations to such people, as they cannot be parties to our contract. This is principally because of the absence of any possibility of mutually advantageous interaction between distant generations. The quality of life of future generations depends to a very large extent on the decisions of the present generation. By contrast, our quality of life is not affected at all by their decisions. We can do a great deal to (or for) posterity but posterity cannot do anything to (or for) us. This power imbalance is often characterised in terms of the absence of Hume's “circumstances of justice”. (The phrase is borrowed from Rawls 1971, pp. 126-130.)For Contractarians, for whom morality is an agreement for mutual advantage, it follows that we have no obligations to future people with whom we cannot interact.

6. Contractualism cannot stop unmoral actions where the people harmed by the action cannot reject the principle that allowed the action. Ashford and Mulgan 5 write:

“Contractualism.” Elizabeth Ashford, Tim Mulgan. [Elizabeth is lecturer in Moral Philosophy at the University of St. Andrews. Tim is a Professor of Moral and Political Philosophy at the University of St. Andrews.] Stanford Encyclopedia of Philosophy. Aug 30, 2007. http://plato.stanford.edu/entries/contractualism/#ConCirRed.

This problem owes its prominence in recent philosophical debate to the work of Derek Parfit, to whom we owe the following example. (Parfit, 1984, pp. 351-379.) The Summer or Winter Child. Mary is deciding when to have a child. She could have one in summer or in winter. Mary suffers from a rare condition which means that, if she has her child in winter, it will suffer serious ailments which will reduce the quality of its life. However, a child born in winter would still have a life worth living, and, if Mary decides to have a child in summer, then an altogether different child will be born. It is mildly inconvenient for Mary to have a child in summer. (Perhaps she doesn't fancy being heavily pregnant during hot weather.) Therefore, she opts for a winter birth. Mary's behaviour seems morally wrong. Utilitarians have a simple account of why Mary's behaviour is wrong, as she brings about less human happiness than she could have done. Yet it seems that Contractualism cannot capture this intuition. Consider a principle permitting Mary's behaviour. If Mary's behaviour is wrong, then this principle must be one that someone can reasonably reject. But who? Not the Winter Child — because he would otherwise never have existed at all. And not the Summer Child — because he doesn't exist.

Contractualism, like Kant's own view, requires that an agent subject her judgments of what she is permitted to do, is required to do, and is prohibited from doing to consideration within a reciprocal framework of justification. The contractualist agent (like the Kantian agent) must have a motivational commitment to acting only on reasons which are acceptable from her impartial perspective. Thus the contractualist model contains a limiting condition similar to the Kantian one. It expresses the agent's commitment that she will not act, unless her action is morally permitted. Her understanding of what is morally permitted, is derived from consideration of what others may do, what others may permit her to do, and what she may permit others to do.